Nosocomial Achromobacter xylosoxidans Infection Presenting as a Cavitary Lung Lesion in a Lung Cancer Patient

Achromobacter xylosoxidans is a Gram-negative bacillus that is known to cause nosocomial infections, primarily in patients with hematological malignancies. The most common primary manifestation is bacteremia. We report a novel case of primary A. xylosoxidans infection presenting as a cavitary lung lesion with associated pneumonia in a lung cancer patient who showed no evidence of malignant disease progression after radiation therapy. Our patient was initially admitted for acute hypoxic respiratory failure requiring mechanical ventilation. Initial computed tomography (CT) revealed a cavitary lesion in the right upper lobe of the lung. Diagnostic bronchoscopy with bronchoalveolar lavage (BAL) was performed and was negative for infectious etiologies including tuberculosis (TB) and fungal infections. Cytology was also negative for malignancy. However, the bacterial culture grew A. xylosoxidans. Antimicrobial therapy was initiated based on culture susceptibilities and the patient showed significant improvement in oxygen requirements. Due to poor functional status, the palliative care route was pursued and mechanical ventilation weaning was not performed. Cavitary pulmonary infections secondary to A. xylosoxidans are rarely reported in the medical literature. After conducting a thorough PubMed database search of the medical literature, we believe this is the first case of A. xylosoxidans infection manifesting as a cavitary lung lesion with associated pneumonia in a lung cancer patient.